But we can use SerNet's repo for CentOS 7. There is another repo available for CentOS 6 also.

Steps are:

1. Go to https://portal.enterprisesamba.com and register.
2. Download the rpms, or better configure yum repo (you will find all there, just add it to /etc/yum.repos.d ).
3. Do a yum install sernet-samba-ad sernet-samba